1. Field of the Invention
The present invention relates to a splicing device which is capable of detecting offset between splicing portions of two elongated tapes when the tapes are spliced along their longitudinal direction, as well as a splicing method.
2. Description of the Related Art
Conventionally, in the process of producing a magnetic tape cassette such as a VHS cassette, a magnetic tape is wound by a winding apparatus into a cassette case which has been assembled in advance in such a state that a pair of reels constituted by a takeup-side reel and a supply-side reel, at which longitudinal ends of a leader tape are respectively retained, are accommodated therein, thereby to complete a magnetic tape cassette.
More specifically, when the magnetic tape is thus wound into the cassette case, the leader tape in the cassette case is first drawn out and is sucked onto a suction table, and the leader tape is cut in the sucked state. Then, one end of the elongated magnetic tape is made to butt against a cut end of the leader tape whose one end is retained at the supply-side reel, the two butting ends are spliced with a splicing tape, and a predetermined length of the magnetic tape is taken up onto the supply-side reel. Subsequently, the magnetic tape is sucked onto the suction table and the magnetic tape is cut, and this cut end and another end of the leader tape whose one end is retained at the takeup-side reel are made to butt against each other and are similarly spliced. Then, the leader tape which has been drawn out from the cassette case and the magnetic tape are finally wound into the cassette, thereby completing the magnetic tape cassette according to the conventional process.
When the magnetic tape and the leader tape are spliced in the above-described production process, there have been cases where the tapes are sucked onto the suction table in a state offset from a proper position due to the effect of a wind or the like, or during the cutting of the tapes, a cutter blade moves the tapes due to its bluntness and the tapes are sucked onto the suction table in a state offset from the proper position. Hence, as shown in FIG. 14, there have been cases where a magnetic tape M and a leader tape L are spliced with a splicing tape S in a mutually offset state.
Accordingly, due to the jutting out of a portion of an adhesive portion of the splicing tape S from the magnetic tape M due to the offset during the splicing of the leader tape L and the magnetic tape M, the jutting-out portion (the aforementioned portion) of the splicing tape S adheres to another portion of the magnetic tape M. As a result, there has been a possibility of the magnetic tape M being cut at the portion where the jutting-out portion of the splicing tape S is adhered.
However, with the conventional winding apparatus, the inspection of the splicing state of the tape is not conducted during the splicing operation, and it has been customary to visually inspect only the spliced state on the side of the takeup-side reel after the completion of the winding of the magnetic tape, or automatically inspect the same by an inspecting machine after the production of the magnetic tape cassette. For this reason, it has been necessary to inspect the spliced portions of the leader tape and the magnetic tape with respect to all the magnetic tape cassettes irrespective of accepted and rejected products, which has been very inefficient. In addition, due to an increase in the number of items to be inspected as a result of inspection of all the cassettes, inspection tends to be unreliable, and there has been an increase in the cost of inspection.